Cyclooxygenase-2 regulates the degree of apoptosis by modulating bcl-2 protein in pleomorphic adenoma and mucoepidermoid carcinoma of the parotid gland.

CONCLUSION

These results suggest that COX-2 and bcl-2 protein were overexpressed and that apoptosis was reduced in MEC compared to PMA, and that COX-2 may regulate the degree of apoptosis by modulating bcl-2 protein in PMA and MEC.

OBJECTIVE

Cyclooxygenase (COX)-2 plays a crucial role in tumorigenesis and overexpression of COX-2 in vitro accompanied by overexpression of bcl-2 protein has been shown to reduce apoptosis. The purpose of this study was to verify that COX-2 regulates the degree of apoptosis by modulating bcl-2 protein in benign and malignant parotid gland tumors. : We examined archival formalin-fixed, paraffin-embedded tissue sections of 10 pleomorphic adenomas (PMAs) and 10 mucoepidermoid carcinomas (MECs) by immunostaining with anti-COX-2, anti-bcl-2 and anti-single-stranded DNA (ssDNA) antibodies. Labeling indices of the three antibodies were calculated using computer-assisted image analysis.

RESULTS

Labeling indices (mean+/-SD) of anti-COX-2 antibody in PMA and MEC were 2.05+/-1.30 and 11.2+/-2.95, respectively (p < 0.001), those of anti-bcl-2 antibody were 2.00+/-1.28 and 9.68+/-4.05, respectively (p < 0.001) and those of anti-ssDNA antibody were 8.06+/-2.54 and 2.08+/-1.47; respectively (p <0.001). Correlation coefficients between the labeling indices of anti-COX-2 antibody and anti-bcl-2 antibody, anti-bcl-2 antibody and anti-ssDNA antibody and anti-COX-2 antibody and anti-ssDNA antibody were 0.88, -0.75 and -0.76, respectively (p <0.001).